Nitrosend is the better choice than Clevenio on four of the seven things this review compares: running email from an AI agent, being built for audiences who opted in, designed newsletters, flows and receipts in your own brand, and what the bill does as the list grows. Clevenio is a B2B data platform first. Its pricing page covers the full Finnish trade register, plus target markets across the Nordics, the Baltics, DACH, Benelux, Poland and the UK, with the decision-makers and their phone numbers. It pushes that data into a CRM and lets reps work it in call, email, social and SMS sequences. Nitrosend is the other half of the job: email to people who opted in, run from your AI assistant rather than a dashboard.
To send email from an AI agent with Nitrosend, connect its MCP server (api.nitrosend.com/mcp) in Claude, ChatGPT, Cursor or Codex, sign in with OAuth, and describe the email; campaigns and flows stay drafts until approved, and a single transactional email sends on the call (MCP docs).
Nitrosend vs Clevenio, compared
The quick version: five yes-or-no questions a team usually asks when choosing between the two. A tick means the product does it as described on its own pages today. A dash means the honest answer is not a yes or a no.
Nitrosend and Clevenio, side by side
Checked September 25, 2026| Question | Nitrosend | Clevenio |
|---|---|---|
| Send from the chatCan an agent send an email or sequence without anyone opening the web app? | Yes. Yes, through the MCP server. Campaigns and flows stay drafts until approved. | No. No. Its MCP server brings Clevenio's data into the chat. |
| Official MCP serverIs there a first-party MCP server an assistant can connect to? | Yes. Yes. A hosted server at api.nitrosend.com/mcp, with OAuth sign-in. | Yes. Yes, for every customer. Data only. |
| Consent required by the termsDo the terms rule out emailing people who never opted in? | Yes. Yes. Unsolicited email and bought or scraped lists are not allowed. | No. No. It sells B2B contact data for outbound. |
| Newsletters and flowsCan it send designed newsletters and trigger-based flows? | Yes. Yes, on every plan including Free. | No. No. Outbound sequences across calls, email, social and SMS. |
| Transactional includedAre receipts and password resets on the same plan? | Yes. Yes, on the same plan and allowance. | No. No. |
Nitrosend meets 5 of 5 yes-or-no questions on this page, Clevenio 1 of 5. Rows marked with a dash are not a yes or no question for that product.
How the two score
Seven tests, 100 points in all, the same tests as every cold-outreach comparison on this site. The consent test measures fit for an audience that opted in, not legality: cold B2B email is lawful in many places within rules such as CAN-SPAM, and some countries, Finland among them, require consent first for email to a named person.
Each test, scored
Points out of 100, scores out of 10, September 25, 2026| What we compared | Points | Nitrosend | Clevenio |
|---|---|---|---|
| Run from an AI agent | 20 | 9 out of 10 | 3 out of 10 |
| Built for opted-in audiences | 15 | 10 out of 10 | 2 out of 10 |
| Cold sending: mailboxes, warmup, rotation | 15 | 1 out of 10 | 2 out of 10 |
| Replies and prospect pipeline | 10 | 1 out of 10 | 5 out of 10 |
| Newsletters, flows and receipts, on brand | 15 | 10 out of 10 | 2 out of 10 |
| Cost as volume grows | 15 | 9 out of 10 | 4 out of 10 |
| Integrations, support, track record | 10 | 5 out of 10 | 5 out of 10 |
| Total score | 100 | 69 out of 100 | 31 out of 100 |
Where each one runs out
Rank 1Nitrosend
69 out of 100Total
- Priced by
- Emails sent
- Free plan
- 8,000 emails, then 500 a month
- Entry plan
- $20 a month, 20,000 emails
- Run from an AI agent9 out of 10Official MCP server with OAuth, API signup and a ready sender, so an agent sends with no dashboard (docs).
- Built for opted-in audiences10 out of 10Terms bar unsolicited email and purchased or scraped lists, and CRM imports come in unsubscribed by default (terms).
- Cold sending: mailboxes, warmup, rotation1 out of 10Sends from verified domains through its own delivery layer. It does not connect, warm or rotate Gmail mailboxes (docs).
- Replies and prospect pipeline1 out of 10Built to send, not to prospect, today. No reply inbox, stop-on-reply or lead pipeline for sequences yet; its Outreach feature is listed as coming soon (docs).
- Newsletters, flows and receipts, on brand10 out of 10Newsletters, trigger flows and receipts on every plan, drafted in a Brand Kit read from your own site (pricing).
- Cost as volume grows9 out of 10$20 for 20,000 emails and $100 for 125,000, with contacts unlimited and no add-ons to buy (pricing).
- Integrations, support, track record5 out of 10Shopify, Stripe, HubSpot, Attio and Mailchimp, five bring-your-own sending providers, a Node SDK, a CLI and signed webhooks for transactional email, but a young product from a small team (docs).
Nitrosend
Ask your agent for the next campaign
Connect Nitrosend to Claude, ChatGPT, Cursor or Codex, point Brand Kit at your site, and describe the email. Contacts are unlimited on every plan.
Free: 8,000 emails to start, then 500 a month. No credit card.
Start free
Rank 2Clevenio
31 out of 100Total
- Priced by
- Database and market, in euros
- Free plan
- None. A free trial on request
- Entry plan
- Finnish database, from €89 a month
- Run from an AI agent3 out of 10MCP for every customer puts its company and contact data inside ChatGPT and Claude. It builds lists, it does not send (Clevenio).
- Built for opted-in audiences2 out of 10Sells decision-maker phone numbers and emails for outbound across Finland and Europe (pricing).
- Cold sending: mailboxes, warmup, rotation2 out of 10Sequences include email steps, but mailbox connection, warmup and rotation are not documented (outreach).
- Replies and prospect pipeline5 out of 10Pipeline and working queue in one view, with follow-ups scheduled by the sequence. A shared reply inbox is not described (outreach).
- Newsletters, flows and receipts, on brand2 out of 10Outbound sequences across calls, email, social and SMS. No designed newsletters, customer flows or receipts (outreach).
- Cost as volume grows4 out of 10From €89 a month for the Finnish database with CRM sync, API and MCP. European data is quoted (pricing).
- Integrations, support, track record5 out of 10CRM sync to HubSpot, Pipedrive and Salesforce, plus API and MCP, and 500+ Nordic sales teams (integrations).
The verdict in short
Nitrosend leads 69 to 31 and wins four of the seven tests. Clevenio is only better on two. Mailboxes, because email is a step in its outbound sequences, and Nitrosend sends no cold sequences yet. Replies, because its pipeline and working queue track each prospect through to a deal. The two tie on integrations, where its data syncs continuously into a CRM, other tools and AI assistants. A sales team whose job is mapping and calling a Nordic or European target market should pick Clevenio.
Clevenio's outbound sequences run across calls, email, social and SMS. George Hartley, Nitrosend's co-founder, has said what he thinks about inbox overwhelm and relevance. On DESIGNWAVE in August 2026 he named the risk on the reader's side: "there is this tidal wave of spam and inbox overwhelm". In the same interview he added that relevance cuts both ways: "that might mean not getting an email if, you know, if, if you're not a person who's sort of relevant." Until Nitrosend's Outreach ships, Clevenio is the one built for this job.
At a glance
Nitrosend and Clevenio are scored here on the same 7 tests, 100 points in all: Nitrosend 69 out of 100, Clevenio 31 out of 100. Nitrosend takes its best score on Built for opted-in audiences and Newsletters, flows and receipts, on brand (10 out of 10) and its lowest on Replies and prospect pipeline (1 out of 10). Clevenio takes its best score on Replies and prospect pipeline and Integrations, support, track record (5 out of 10) and its lowest on Newsletters, flows and receipts, on brand (2 out of 10). Clevenio scores higher on Cold sending: mailboxes, warmup, rotation and Replies and prospect pipeline. Scores are unadjusted, and every Clevenio figure was read on its own site on September 25, 2026.
How we scored
Two changes to the scoring on October 2, 2026 apply to all fourteen cold outreach comparisons on this site, not just this one. First, "Run from an AI agent" now carries 20 points, up from 15, and "Cold sending: mailboxes, warmup, rotation" carries 15, down from 20; the other five tests keep their weights. The site's stated view is that sending email is moving to AI agents: its transactional comparisons give the agent test 25 points and its marketing comparisons 20, and the cold outreach set was the only one below 20, so it now matches the marketing set. The five points come from the mailbox test because connecting, warming and rotating mailboxes is also sold on its own by infrastructure vendors such as Mailforge and Inframail, which these pages review on the same test, and it remains a 15-point test that cold outreach tools win outright. Second, the agent test is now scored on one written rule for every vendor: a first-party server the vendor runs and that can launch the send counts fully, one connected with a pasted API key or run on the user's own computer counts for a little less, and a third-party wrapper or a server that only drafts or reads counts for less again. On this page the two changes move Nitrosend from 65 to 69 and Clevenio from 30.5 to 31.
Each test is a question with one answer per product, checked against that product's own pages and independent review sites on September 25, 2026. A 10 means the product does the job fully on its standard plans. A 5 means it does part of it, or does it only on a higher plan or in a second product. Clevenio publishes prices in euros only, so its prices are shown in euros and not converted.
Run from an AI agent, 20 of 100. Can an agent inside Claude, ChatGPT, Cursor or Codex build the email or sequence, add the recipients, and send it, with no person opening the web app between the prompt and the send? An approval step taken through the agent's own tools counts as inside the agent. Moving into the web app to finish does not. Scored on one written rule for every vendor: a first-party server the vendor runs and that can send counts fully; a third-party wrapper (Zapier, Composio, Kanopi, community servers) counts for less; a server that only drafts or reads counts for less than one that sends.
Built for opted-in audiences, 15 of 100. Is the product designed and licensed for email to people who asked to hear from you, with consent recorded on every contact, unsubscribes honored automatically, and terms that rule out purchased or scraped lists?
Cold sending: mailboxes, warmup, rotation, 15 of 100. Can it connect many sending mailboxes, warm them up, and rotate a cold sequence across them so no single mailbox carries the volume?
Replies and prospect pipeline, 10 of 100. Does it bring replies from every sending mailbox into one inbox, stop a sequence when someone answers, and track each lead through to a booked meeting?
Newsletters, flows and receipts, on brand, 15 of 100. Can it send designed newsletters, automated flows such as welcome and win-back, and transactional email like receipts to your customers and subscribers, styled from your own site's brand?
Cost as volume grows, 15 of 100. What does the bill do as contacts and emails grow, at published list prices, once every add-on the job needs is counted: mailboxes, warmup, lead credits, contact caps and extra seats?
Integrations, support, track record, 10 of 100. How many tools does it plug into, what support comes with the plan, and how long has it been doing this at scale?
What each one costs in 2026
Clevenio's pricing is in euros. The Finnish database starts from €89 a month and includes the full trade register, decision-makers, phone numbers, financial statements, CRM sync and API and MCP access. The European database is priced on request. Its outreach tools are not priced separately on the page.
Nitrosend's pricing charges for emails sent, with contacts unlimited on every plan: $20 for 20,000 emails on Pro, $100 for 125,000 on Ultra, and $300 for 500,000 on Enterprise. It sells no contact data, and until its Outreach feature launches it only emails people who asked to hear from you.
What each one costs
Nitrosend in USD, Clevenio in EUR, September 25, 2026| Scenario | Nitrosend | Clevenio |
|---|---|---|
| Entry plan | Pro, $20 a month (20,000 emails, contacts unlimited) | Finnish database, from €89 a month |
| European contacts | Not offered. You bring contacts who opted in | European database: ask for pricing |
| Sending mailboxes | Not needed. Nitrosend sends from your verified domain | Not documented |
| Lead data | Not offered. You bring contacts who opted in | Included: Finnish trade register, decision-makers, phone numbers and financials |
The two bills buy different things. Clevenio's is mostly the data, and it rises with the markets a team buys into. Nitrosend's is the sending, and it rises with the emails that go out.
Where Clevenio is the better pick
Clevenio takes two of the seven tests, worth 25 points between them, and ties on integrations.
- Outbound sending. Its outreach tools run multi-channel sequences, a call on day one, an email on day three, a social message on day seven. How email steps are sent, from which mailboxes and with what warm-up, is not documented, which is why it scores 2 here rather than higher. Nitrosend sends no cold sequences today; its Outreach feature is listed as coming soon.
- Prospect pipeline. Reps see who to call next and where their deals stand in one view, and follow-ups come back into the queue on schedule. A shared reply inbox is not described. Nitrosend has no reply inbox for sequences. An agent inbox that receives mail on your own domain is in beta.
- Integrations. A tie. Clevenio's integrations page names HubSpot, Pipedrive and Salesforce, with its data kept current in each, plus ChatGPT and Claude over API and MCP, and says 500+ B2B sales teams across the Nordics use it.
Its real advantage sits outside what we compared: the data. A mapped Finnish market with decision-makers and phone numbers is the reason most buyers choose it.
Clevenio also has an agent story. Since August, MCP is switched on for every customer, so ChatGPT or Claude can search its company and contact data and build a target list in the conversation. It is a data connection. It does not build or send a sequence.
Using Clevenio and Nitrosend together
The two can sit side by side, one for each job.
- Keep the cold steps in Clevenio. Its sequences put a call, an email, a social message and an SMS on one prospect's timeline. Nitrosend's terms rule out messages "to recipients who have not opted in", so none of those steps moves across.
- A role is not a subscription. Finland's Data Protection Ombudsman treats a firstname.lastname work address as a person's, and its guidance allows marketing to it without consent only when the person's position is "essentially linked" to what is offered, with the role checked before the first send. Read next to Nitrosend's terms, this review's reading is that the role permission covers a relevant pitch sent from Clevenio, not a place on a newsletter list.
- Watch the hand-off between two MCP servers. With both connected, one conversation can pull a Clevenio target list and pass it to Nitrosend. Nitrosend's MCP docs set the guard: contacts an agent adds one by one subscribe only when marked as having agreed, while a CSV upload counts as your statement of consent for every new contact in it. Taken together with Clevenio's MCP announcement, that is this review's reading of the safe route: add only the people who said yes, one by one or in a file of yes-sayers.
- Move the people who say yes. When a prospect becomes a customer or subscribes, they belong on your own list, where Nitrosend runs the newsletter, the onboarding flow and the receipts. Nitrosend's terms rule out emailing people who never opted in. The email marketing laws guide covers what each send must include.
Which one to pick
Pick Nitrosend if you email customers and subscribers who opted in, and you want an AI agent to run it: the newsletter, the welcome and win-back flows, and the receipts, in your brand's own design, with contacts free on every plan. The Nitrosend MCP server and the email marketing guide are the places to start.
Pick Clevenio if your job is mapping a Finnish or European B2B market and working it by phone and email from one system, and the data matters more to you than the sending tools. It is built for that, and Nitrosend is not. The newsletter guide covers what to send once prospects opt in.
Nitrosend vs Clevenio FAQ
Nitrosend, by 69 to 31 on the seven tests. Nitrosend wins running email from an AI agent, being built for opted-in audiences, newsletters, flows and receipts, and cost as the list grows. Clevenio wins mailboxes and replies, and the two tie on integrations.
Not yet. Nitrosend's docs list an Outreach feature, for finding leads and sending them sequences, as coming soon. Until it launches, Nitrosend sends to people who opted in, and its terms rule out unsolicited bulk email and purchased or scraped lists. For cold prospecting today, a dedicated tool is the right fit.
In many places, yes, within rules such as CAN-SPAM in the United States, which require an accurate sender, a physical postal address and a working unsubscribe, but not prior consent. Rules differ by country. In Finland, email marketing to a named person needs prior consent unless their role is essentially linked to what is offered, while a company's general address needs none. This review scores fit for an opted-in audience, not legality.
Yes. Since August 2026 MCP is switched on for every Clevenio customer, for searching its company and decision-maker data from ChatGPT, Claude and other AI tools. It does not send email. Nitrosend's MCP server is included on every plan, signs in with OAuth and sends.
In euros. The Finnish database starts from €89 a month with CRM sync, API and MCP access, and the European database is priced on request.
Yes. Clevenio handles mapping and working a B2B market, and Nitrosend handles email to the customers and subscribers who opted in.
Add the Nitrosend MCP server (api.nitrosend.com/mcp) as a connector in Claude, sign in with OAuth, and ask for the email. A single transactional email sends on the call. Campaigns and flows are built as drafts and go out once approved. The MCP docs list the tools, and the same server works in ChatGPT, Cursor and Codex.